Endoluminal anchor

ABSTRACT

Disclosed is an anastomosis catheter, for achieving a tissue to tissue or synthetic graft to tissue attachment. The catheter includes a plurality of deployable tissue anchors, which may be laterally deployed into surrounding tissue. The anchors may be used to achieve end to end or end to side anastomoses. Methods are also disclosed.

This application is a divisional of application Ser. No. 09/482,986filed Jan. 11, 2000 which is a continuation-in-part of application Ser.No. 09/399,521, filed Sep. 20, 1999, now U.S. Pat. No. 6,231,561 thedisclosure of which is incorporated in its entirety herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to methods and devices for performinganastomosis. More particularly, the present invention relates to methodsand devices for performing tissue-to-tissue or synthetic graft-to-tissuevascular anastomosis under either direct or transluminal access.

Anastomosis is the union or joinder of one hollow vessel or structure toanother so that the interior of the vessels communicate with oneanother. There are generally two types of vascular anastomosis:end-to-end and end-to-side. In an end-to-end anastomosis, the severedend of a first vessel or an end of a synthetic graft is coupled, usuallyby suturing or stapling, to the severed end of a second vessel. In thecontext of a synthetic vascular graft, the ends and possiblyintermediate portions of the graft may be secured to the wall of thevessel without removing a portion of the native vessel. In anend-to-side anastomosis, the severed end of a first vessel or an end ofa synthetic graft is connected around an opening cut into the side of asecond vessel.

Anastomoses are performed in a variety of anatomies, such as betweenairways, blood vessels, bowels, and urogenital lumens. The procedure forconnecting blood vessels is referred to as vascular anastomosis. One ofthe best known surgical procedures utilizing vascular anastomosis is thecoronary bypass. In the context of coronary artery disease, the flow ofoxygenated blood to the myocardium of the heart is inhibited by astenosis or obstruction in the coronary artery. This flow can beimproved by providing a coronary artery bypass graft (“CABG”) betweenthe aorta and a point in the coronary artery distal to the stenosis.Typically, a section of vein from the leg is removed and attached at oneend to the aorta and at the other end to the coronary artery utilizingend-to-side anastomosis. Such grafts are known as saphenous coronaryartery bypass grafts. Alternatively, synthetic grafts can be utilized toeffect the bypass.

While the typical coronary bypass procedure favorably affects theincidence and severity of angina in patients with coronary arterydisease, a variety of risks are associated with such procedures. Amongthem are mortality, myocardial infarction, postoperative bleeding,cerebrovascular accident, arrhythmias, wound or other infection, aorticdissection and limb ischemia. Furthermore, the vein grafts deteriorateover time, thereby resulting in the recurrence of angina, myocardialinfarction and death. In addition, the costs of such procedures arerelatively high and the patient recovery relatively long.

In an attempt to overcome such problems, a number of alternativeapproaches have been developed. For example, artery to artery bypassprocedures have been utilized in which an arterial source of oxygenatedblood-such as the left internal mammary artery (“LIMA”), right internalmammary artery (“RIMA”), or right internal thoracic artery (“RITA”)—issevered and anastomosed to the obstructed coronary artery distally tothe stenosis or occlusion. More recently, other arteries have been usedin such procedures, including the inferior epigastria arteries andgastroepiploic arteries. In general, artery to artery bypass procedureshave demonstrated a better patency rate as compared with autologous veinor synthetic grafts.

While vascular anastomosis can be effective, and sometimes life-savingprocedures, traditionally available techniques have been associated witha number of complications. For example, conventional techniques forperforming vascular anastomosis generally require an extensive incisionin the patient's body. Such operations are traumatic to the patient,involve a lengthy recovery, and a relatively high risk of infection orother complications.

In the context of coronary bypass surgery, for example, the bypass graftor artery-to-artery procedure is traditionally performed using an openchest procedure. In particular, each procedure involves the necessity ofa formal 20 to 25 cm incision in the chest of the patient, severing thesternum and cutting and peeling back various layers of tissue in orderto give access to the heart and arterial sources. As a result, theseoperations typically require large numbers of sutures or staples toclose the incision and 5 to 10 wire hooks to keep the severed sternumtogether. Furthermore, such procedures leave an unattractive scar andare painful to the patient. Most patients are out of work for a longperiod after such an operation and have restricted movement for severalweeks. Such surgery often carries additional complications such asinstability of the sternum, post-operative bleeding and mediastinalinfection. Above all, open procedures are associated with longrecuperation times.

Due to the risks attendant to such procedures, there has been a need todevelop procedures which minimize invasion of the patient's body tissueand resulting trauma. In this regard, limited open chest techniques havebeen developed in which the coronary bypass is carried out using anabdominal (subxyphoid) approach or, alternatively, a “Chamberlain”incision (an approximately 8 cm incision at the sternocostal junction),thereby lessening the operating area and the associated complicationrate. While the risks attendant to such procedures are generally lowerthan their open chest counterparts, there is still a need for aminimally invasive surgical technique. Nevertheless, each of thesetechniques is thoracotomic, requiring an incision to be made in thechest wall through which conventional surgical instruments areintroduced to perform conventional coronary bypass surgery.

In order to reduce the risk of patient mortality, infection, and othercomplications associated with surgical techniques, it is advantageousand desirable to utilize endoscopic and thoracoscopic surgicaltechniques. Such procedures usually involve the use of surgical trocarsto puncture the abdomen or chest, thereby facilitating access to a bodycavity through the cannula and a relatively small opening in thepatient's body. Typically, such trocars have a diameter of about 3 mm to15 mm. Surgical instruments and other devices such as fiber opticcameras can be inserted into the body cavity through the cannula.Advantageously, the use of trocars minimizes the trauma associated withmany surgical procedures.

Another application involves the implantation and/or attachment ofsynthetic vascular grafts. Tubular vascular grafts comprisingpolytetrafluoroethylene (PTFE), Dacron, or other fabric materials may beimplanted in a vessel to span a diseased or damaged site. In thisapplication, the diseased portion of the vessel is merely isolated bydirecting blood flow through the graft. This may be accomplished byattaching the proximal end and distal end of the graft to the vesselwall proximally and distally of the diseased site. In somecircumstances, portions of the graft in between the proximal and distalends are preferably also attached to the vessel wall, to maintainpatency throughout the graft. One application of such grafts is to treatabdominal aortic aneurysms, by implanting either a straight segmentgraft or a Y shaped “bifurcation” graft at the bifurcation of the lowerabdominal aorta and the left and right iliac arteries.

When vascular anastomoses are performed, the goal is to achieve asufficiently leak-proof connection between tubular structures.Typically, such connections in a CABG procedure are established usingsuturing techniques. Suturing of vascular structures, however, is atedious and time consuming process. Furthermore, current suturingtechniques are not possible using transluminal access, and are notreadily adapted for endoscopic use, where the surgeon's freedom ofaccess and movement are limited. Thus, there is a need for analternative to current suturing techniques that would expedite theanastomosis procedure, and that can be readily adapted for transluminalor endoscopic use.

Various stapling techniques are also known for providing anastomoticconnections between organs, such as in intestinal and colorectalanastomosis. Due to the size of these devices, however, they are noteasily adapted for use with vascular organs in general, and particularlynot for transluminal or endoscopic techniques.

Surgical clips have also been developed, which are intended tofacilitate the anastomosis of vascular structures. In this technique,the vascular tissues are approximated, partially everted, and thenclipped by applying the arms of the surgical clip over the evertedtissue and securing the clip so as to hold the tissue together withoutpenetrating the interior wall of the vessel. Nevertheless, in order toproperly utilize these clips, the tissues should be everted. Atransluminal approach is thus not readily possible using this technique.

Thus, notwithstanding the various efforts in the prior art, thereremains a need for methods and devices for performing vascularanastomoses which minimize the risk of infection, trauma, and othercomplications associated with conventional surgery, and, in particular,which can be utilized transluminally or in conjunction with anendoscopic technique for vascular anastomosis.

SUMMARY OF THE INVENTION

There is provided in accordance with one aspect of the presentinvention, a method of attaching a tubular graft to a vessel wall. Themethod comprises the steps of positioning a tubular graft within avessel, and positioning a tissue anchor deployment catheter at a firstposition within the graft, the deployment catheter comprising a firstplurality of tissue anchors. The anchors are thereafter advanced intothe vessel wall, to secure the graft to the vessel wall. In oneembodiment, the advancing the anchors step comprises advancing theanchors through the graft and into the vessel wall. Preferably, theadvancing the anchors step comprises advancing at least four anchorsinto the vessel wall. In one embodiment, the positioning a graft stepcomprises positioning a tubular PTFE graft. Preferably, the methodfurther comprises the step of advancing a catheter to a second positionwithin the graft, and advancing a second plurality of anchors into thevessel wall. This may be accomplished using a second plurality ofanchors, carried by the catheter.

In accordance with another aspect of the present invention, there isprovided a method of attaching a first tubular structure to a secondtubular structure in a patient. The method comprises the steps ofidentifying a first tubular structure in the patient, and positioning asecond tubular structure in communication with the first tubularstructure. An anchor deployment catheter is positioned within at leastone of the first and second tubular structures. A plurality of tissueanchors are deployed from the catheter and through at least one of thefirst and second tubular structures, to attach the first tubularstructure to the second tubular structure. The first tubular structuremay be an artery or a vein, and the second tubular structure may be agraft. The graft may be autologous vessel tissue, a homograft, axenograft, or a prosthetic tubular graft.

In accordance with a further aspect of the present invention, there isprovided an anastomosis catheter. The anastomosis catheter comprises anelongate flexible body, having a proximal end and distal end. At leastone tissue anchor support is provided on the body, moveable between anaxial orientation and an inclined orientation. An anchor is movablycarried by the anchor support. The anchor comprises a body, having atleast one proximal engagement surface for resisting distal travel of thebody through the tissue and at least one distal engagement surface forresisting proximal travel of the body through tissue.

In one embodiment, the tissue anchor support comprises a tube. The tubecomprises a proximal section, a distal section and a hinge in-betweenthe proximal section and the distal section. An actuator is preferablyconnected to the distal section, so that proximal retraction of theactuator with respect to the catheter body advances the anchor supportfrom the axial position to the inclined position. Preferably, thecatheter further comprises an introducer removably connected to theanchor for driving the anchor into the tissue. Preferably, the cathetercomprises from about four anchor supports to about eight anchorsupports.

In accordance with another aspect of the present invention, there isprovided a method of tacking a tubular graft to a vessel wall. Themethod comprises the steps of identifying a tubular graft which has beenpreviously positioned within a vessel. A tissue anchor deploymentcatheter is positioned within the graft, the deployment cathetercomprising at least one tissue anchor. The anchor is thereafter advancedinto the vessel wall, to secure the graft to the vessel wall.

Further features and advantages of the present invention will becomeapparent to those of skill in the art in view of the detaileddescription of preferred embodiments which follows, when consideredtogether with the attached drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an anterior illustration of a heart, with the proximal partsof the great vessels.

FIG. 2 is a schematic cross section through the heart with a transeptalcatheter deployed through the septum and a closure catheter extendinginto the LAA.

FIG. 3 is an enlarged perspective view of the distal end of a closurecatheter in accordance with the present invention.

FIG. 3B is a cross section taken along the lines 3B—3B of FIG. 3A.

FIG. 4 is a partial cross-sectional view of a tissue anchor andintroducer, positioned within an anchor guide in accordance with thepresent invention.

FIG. 5 is an exploded view of a tissue anchor and introducer inaccordance with one aspect of the invention.

FIG. 6A is a schematic illustration of a tissue anchor and introduceradvancing into a tissue surface.

FIG. 6B is an illustration as in FIG. 6A, with the anchor positionedwithin the tissue and the introducer partially retracted.

FIG. 6C is an illustration as in FIG. 6B, with the introducer fullyretracted and the anchor positioned within the tissue.

FIG. 7 shows a schematic view of a closure catheter disposed within theopening of the LAA.

FIG. 8 is a schematic illustration of the opening of the LAA as in FIG.7, with the anchor guides in an inclined orientation.

FIG. 9 is a schematic illustration as in FIG. 8, with tissue anchorsdeployed from the anchor guides.

FIG. 10 is a schematic illustration as in FIG. 9, with the anchor guidesretracted into an axial orientation.

FIG. 11 is a schematic illustration as in FIG. 10, with the closurecatheter retracted and the LAA drawn closed using the tissue anchors.

FIG. 12 is a schematic cross-sectional view of an anastomosis catheterpositioned within a synthetic tubular graft at a site in a body lumen.

FIG. 13 is a schematic illustration as in FIG. 6A, with an anchorpartially deployed through the graft and vessel wall.

FIG. 14 is a schematic illustration as in FIG. 13, and similar to FIG.6C, showing the anastomosis anchor fully deployed.

FIGS. 15A-15G are alternate tissue anchors for use with the closurecatheter of the present invention.

FIG. 16 is a perspective view of a buckling rivet type anchor inaccordance with the present invention.

FIG. 17 is a perspective view of the buckling rivet of FIG. 16, carriedby an introducer.

FIG. 18 is a cross-sectional schematic view of a buckling rivet of thetype shown in FIG. 16, deployed on a tissue membrane.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

For simplicity, the present invention will be described primarily in thecontext of a left atrial appendage closure procedure, and as modifiedfor use in tissue-to-tissue or synthetic graft-to-tissue anastomosis. Asused herein the term “anastomosis” shall include securing a tubularsynthetic graft within a vessel, such as to span an aneurysm, as well asthe end to end and end to side orientation discussed in the Backgroundof the Invention. However, the device and methods herein are readilyapplicable to a wider variety of closure or attachment procedures, andall such applications are contemplated by the present inventors. Forexample, additional heart muscle procedures such as atrial septal defectclosure and patent ductus arteriosis closure are contemplated. Vascularprocedures such as isolation or repair of aneurysms, anastomosis ofvessel to vessel or vessel to prosthetic tubular graft (e.g., PTFE orDacron tubes, with or without wire support structures as are well knownin the art) joints may also be accomplished using the devices of thepresent invention. Attachment of implantable prostheses, such asattachment of the annulus of a prosthetic tissue or mechanical heartvalve may be accomplished. A variety of other tissue openings, lumens,hollow organs and surgically created passageways may be closed, patchedor reduced in volume in accordance with the present invention. Forexample, an opening in a tissue plane may be closed or patched, such asby attaching a fabric or tissue sheet across the opening. In onespecific application, the device of the present invention is used toanchor a fabric patch to close an atrial septal defect. The targetaperture or cavity may be accessed transluminally (e.g., vascularcatheter or endoscope) or through solid tissue, such as transmural,percutaneous or other approach. The present invention may also be usedin an open surgical procedure such as to close the left atrial appendageduring open heart surgery to correct or address a different condition.In another example, the device is advanced through the percutaneousopening and used to close a vascular puncture such as a femoral arteryaccess site for a PTA or other diagnostic or therapeutic interventionalprocedure. Adaptation of the devices and methods disclosed herein toaccomplish procedures such as the foregoing will be apparent to those ofskill in the art in view of the disclosure herein.

Referring to FIG. 1, a heart 10 is illustrated to show certain portionsincluding the left ventricle 12, the left atrium 14, the left atrialappendage (LAA) 16, the pulmonary artery 18, the aorta 20, the rightventricle 22, the right atria 24, and the right atrial appendage 26. Asis understood in the art, the left atrium 14 is located above the leftventricle 12 and the two are separated by the mitral valve (notillustrated). The LAA 16 is normally in fluid communication with theleft atrium 14 such that blood flows in and out of the LAA 16 as theheart 10 beats.

In accordance with the present invention, a closure catheter 38 isadvanced through the heart and into the LAA. In general, the closurecatheter 38 is adapted to grasp tissue surrounding the opening to theLAA, and retract it radially inwardly to reduce the volume of and/orclose the LAA. The LAA is thereafter secured in its closed orientation,and the closure catheter 38 is removed. Specific aspects of oneembodiment of the closure catheter in accordance with the presentinvention are described in greater detail below.

The LAA may be accessed through any of a variety of pathways as will beapparent to those of skill in the art. Transeptal access, ascontemplated by FIG. 2, may be achieved by introducing a transeptalcatheter through the femoral or jugular vein, and transluminallyadvancing the catheter into the right atrium. Once in the right atrium,a long hollow needle with a preformed curve and a sharpened distal tipis forcibly inserted through the fossa ovalis. A radiopaque contrastmedia may then be injected through the needle to allow visualization andensure placement of the needle in the left atrium, as opposed to beingin the pericardial space, aorta, or other undesired location.

Once the position of the needle in the left atrium is confirmed, thetranseptal catheter is advanced into the left atrium. The closurecatheter 38 may then be advanced through the transeptal catheter 30, andsteered or directed into the left atrial appendage. Alternativeapproaches include venous transatrial approaches such as transvascularadvancement through the aorta and the mitral valve. In addition, thedevices of the present invention can be readily adapted for use in anopen heart surgical procedure, although transluminal access is presentlypreferred.

Thus, referring to FIG. 2, a transeptal catheter 30 has a proximal end32 and a distal end 34. The distal end 34 of the transeptal catheter 30has breached the septum 40 of the patient's heart 10 and is disposedadjacent the opening 42 of the patient's LAA 16. The distal end 36 of aclosure catheter 38 extends from the distal end 34 of the transeptalcatheter 30 and into the LAA 16.

At the proximal end 46 of the transeptal catheter 30, a luer connectorcoupled to a hemostasis valve 48 prevents the egress of blood from acentral lumen of the transeptal catheter 30. The proximal end 50 of theclosure catheter 38 extends proximally from the hemostasis valve 48.Additional details concerning the use and design of transeptal accesscatheters are well known in the art and will not be discussed furtherherein.

Referring to FIGS. 2 and 3, the closure catheter 38 thus has a proximalend 50, a distal end 36, and an elongate flexible tubular body 52extending therebetween. The axial length of the closure catheter 38 canbe varied, depending upon the intended access point and pathway. For afemoral vein-transeptal approach, the closure catheter 38 generally hasan axial length within the range of from about 100 cm to about 140 cm,and, in one embodiment, about 117 cm.

The outside diameter of the flexible body 52 can also be varied,depending upon the number of internal lumen and other functionalities aswill be understood by those of skill in the art. In one embodiment, theoutside diameter is about 12 FR (0.156 inches), and closure cathetersare contemplated to have OD's generally within the range of from about0.078 inches to about 0.250 inches. Diameters outside of the above rangemay also be used, provided that the functional consequences of thediameter are acceptable for the intended application of the catheter.

For example, the lower limit of the outside diameter for tubular body 52in a given application will be a function of the number of fluid orother functional lumen contained within the catheter. In addition,tubular body 52 must have sufficient pushability to permit the catheterto be advanced to its target location within the heart without bucklingor undesirable bending. The ability of the tubular body 52 to transmittorque may also be desirable, such as in embodiments in which the tissueanchor deployment guides are not uniformly circumferentially distributedabout the distal end 36 of the catheter. Optimization of the outsidediameter of the catheter, taking into account the flexibility,pushability and torque transmission characteristics can be accomplishedthrough routine experimentation using conventional catheter designtechniques well known to those of skill in the art.

The flexible body 52 can be manufactured in accordance with any of avariety of known techniques. In one embodiment, the flexible body 52 isextruded from any of a variety of materials such as HDPE, PEBAX, nylon,polyimide, and PEEK. Alternatively, at least a portion or all of thelength of tubular body 52 may comprise a spring coil, solid walledhypodermic needle or other metal tubing, or braided reinforced wall, asare known in the art.

The proximal end 50 of the closure catheter 38 is provided with amanifold 51, having a plurality of access ports. Generally, manifold 51is provided with an access port 53 which may be used as a guidewire portin an over the wire embodiment, and a deployment wire port 57.Additional access ports such as a contrast media introduction port 55,or others may be provided as needed, depending upon the functionalrequirements of the catheter.

The tubular body 52 has at least a first actuator lumen 54, for axiallymovably receiving an actuator 56. Actuator 56 extends between a proximalend 64 at about the proximal end of the closure catheter, and a distalend 66 at or near the distal end 36 of the closure catheter 38. Thedistal end 66 of the actuator 56 is secured to a cap 68. In theillustrated embodiment, the actuator lumen 54 is in communication withthe access port 53 to permit the actuator 56 to extend proximallytherethrough.

Actuator 56 can have a variety of forms, depending upon the constructionof the anchor supports 62 on the distal end 36 of the closure catheter38. In general, the catheter in the area of the anchor supports 62should have a crossing profile of no more than about 14 French fortransluminal advancement and positioning. However, the anchor supportsmust then be capable of directing tissue anchors into the wall of thecavity or lumen which may have an inside diameter on the order of about1.5 cm to about 3 cm in the case of the LAA in an average adult. Thedevice of the present invention can be readily scaled up or downdepending upon the intended use, such as to accommodate a 5 cm to 10 cmcavity in GI tract applications or 5 mm to about 2 cm for vascularapplications. For this purpose, the anchor supports are preferablymoveable between a reduced cross sectional orientation and an enlargedcross sectional orientation to aim at, and, in some embodiments, contactthe target tissue surface.

One convenient construction to accomplish the foregoing is for eachanchor support 62 to take the form of a lever arm structure which ispivotably connected at one end to the catheter body. This constructionpermits inclination of the anchor support throughout a continuous rangeof outside diameters which may be desirable to aim the anchor andaccommodate different treatment sites and/or normal anatomical variationwithin the patient population.

A laterally moveable anchor support can be moved between an axialorientation and an inclined orientation in a variety of ways. Oneconvenient way is through the use of a pull wire or other actuator whichincreases the diameter of the deployment zone of the catheter inresponse to an axial shortening of fixed length moveable segments asdisclosed in more detail below. For this construction, the actuator willbe under pulling tension during actuation. Any of a variety ofstructures such as polymeric or metal single or multiple strand wires,ribbons or tubes can be used. In the illustrated embodiment, theactuator 56 comprises stainless steel tube, having an outside diameterof about 0.025 inches.

A pull wire can alternatively be connected to the radially outwardlyfacing surface and preferably near the distal end of each anchorsupport, and each anchor support is hingably attached at its proximalend to the catheter. Proximal traction on the pull wire will cause theanchor support to incline radially outwardly in the distal direction,and toward the target tissue.

In an alternate construction, the anchor support is inclined under acompressive force on the actuator 56. For example, the embodimentdescribed in detail below can readily be converted to a push actuatedsystem by axially immovable fixing the distal end of the anchor guideassembly to the catheter and slideably pushing the proximal end of theanchor guide assembly in the distal direction to achieve axialcompression as will become apparent from the discussion below.

Push wire actuators have different requirements, than pull actuatorsystems, such as the ability to propagate a sufficient compressive forcewithout excessive compression bending or friction. Thus, solid corewires or tubular structures may be preferred, as well as larger outsidediameters compared to the minimum requirements in a pull actuatedsystem. Thus, the inside diameter of the actuator lumen 57 may bevaried, depending upon the actuator system design. In the illustratedembodiment, the actuator lumen 57 has an ID of about 0.038 inches, toslideably accommodate the 0.025 inch OD actuator 56.

A radially outwardly directed force on the anchor supports 62 can beprovided by any of a variety of alternative expansion structures,depending upon desired performance and construction issues. For example,an inflatable balloon can be positioned radially inwardly from aplurality of hingably mounted anchor supports 62, and placed incommunication with actuator lumen 54 which may be used as an inflationlumen. Any of a variety of balloon materials may be used, ranging inphysical properties from latex for a highly compliant, low pressuresystem to PET for a noncompliant high pressure and consequently highradial force system, as is understood in the balloon angioplasty arts.

The tubular body 52 may additionally be provided with a guidewire lumen57, or a guidewire lumen 57 may extend coaxially throughout the lengthof a tubular actuator 56 as in the illustrated embodiment.

The tubular body 52 may additionally be provided with a deployment lumen58, for axially movably receiving one or more deployment elements 60such as a wire, or suture for deploying one or more tissue anchors 90into the target tissue 110. Deployment force for deploying the tissueanchors 90 can be designed to be in either the distal or proximaldirection, and many of the considerations discussed above in connectionwith the actuator 56 and corresponding actuator lumen 54 apply to thedeployment system as well. In the illustrated embodiment, deployment ofthe tissue anchors 90 is accomplished by proximal retraction on thedeployment element 60 which, in turn, retracts deployment wire 106.Pushability is thus not an issue, and common suture such as 0.008 inchdiameter nylon line may be used. For this embodiment, deployment lumen58 has an inside diameter of about 0.038 inches. The deployment lumen 58can be sized to receive either a single deployment element 60, or aplurality of deployment elements 106 such as a unique suture for eachtissue anchor.

The distal end 36 of the closure catheter 38 is provided with one ormore anchor supports 62, for removably carrying one or more tissueanchors. Preferably, two or more anchor supports 62 are provided, and,generally, in a device intended for LAA closure, from about 3 to about12 anchor supports 62 are provided. In the illustrated embodiment, sixanchor supports 62 are evenly circumferentially spaced around thelongitudinal axis of the closure catheter 38.

Each anchor support 62 comprises a surface 63 for slideably retaining atleast one tissue anchor, and permitting the tissue anchor to be aimed bymanipulation of a control on the proximal end 50 of the closure catheter38. Specific details of one embodiment of the anchor support 62 having asingle anchor therein will be discussed below. Multiple anchors, such astwo or three or more, can also be carried by each anchor support forsequential deployment.

The anchor supports 62 are movable between an axial orientation and aninclined orientation, in response to manipulation of a proximal control.The proximal control can take any of a variety of forms, such as sliderswitches or levers, rotatable levers or knobs, or the like, dependingupon the desired performance. For example, a rotatable knob control canpermit precise control over the degree of inclination of the anchorsupports 62. A direct axial slider control, such as a knob or other gripdirectly mounted to the actuator 56 will optimize tactile feedback ofevents such as the anchor supports 62 coming into contact with thetarget tissue.

Each of the illustrated anchor supports 62 comprises at least a proximalsection 70, a distal section 72, and a flex point 74. See FIG. 4. Thedistal end 73 of each distal section 72 is movably connected to thecatheter body or the cap 68. In this embodiment, proximal retraction ofthe actuator 56 shortens the axial distance between the proximal end 71of the proximal section 70 and the distal end 73 of distal section 72,forcing the flex point 74 radially outwardly from the longitudinal axisof the closure catheter 38. In this manner, proximal retraction of theactuator 56 through a controlled axial distance will cause a predictableand controlled increase in the angle between the proximal and distalsections 70 and 72 of the anchor support 62 and the longitudinal axis ofthe catheter. This is ideally suited for aiming a plurality of tissueanchors at the interior wall of a tubular structure, such as a vessel orthe left atrial appendage.

Referring to FIG. 4, there is illustrated an enlarged detailed view ofone anchor support 62 in accordance with the present invention. Theproximal section 70 and distal section 72 preferably comprise a tubularwall 76 and 78 joined at the flex point 74. In one embodiment, theproximal section 70 and distal section 72 may be formed from a singlelength of tubing, such as by laser cutting, photolithography, orgrinding to separate the proximal section 70 from the distal section 72while leaving one or two or more integrally formed hinges at flex point74. Any of a variety of polymeric or metal tubing may be utilized forthis purpose, including stainless steel, Nitinol or other super-elasticalloys, polyimide, or others which will be appreciated by those of skillin the art in view of the disclosure herein.

In the illustrated six tube embodiment, the proximal section 70 anddistal section 72 are formed from a length of PEEK tubing having aninside diameter of about 0.038 inches, an outside diameter of about0.045 inches and an overall length of about 1.4 inches. In general, ifmore than six anchor supports 62 are used, the diameter of each will becommensurately less than in the six tube embodiment for any particularapplication. When the proximal section 70 and the distal section 72 arecoaxially aligned, a gap having an axial length of about 0.030 isprovided therebetween. In the illustrated embodiment, the proximalsection 70 and distal section 72 are approximately equal in lengthalthough dissimilar lengths may be desirable in certain embodiments. Thelength of the portion of the anchor support 62 which carries the tissueanchor 90 is preferably selected for a particular procedure or anatomyso that the anchor support 62 will be inclined at an acceptable launchangle when the deployment end of the anchor support 62 is brought intocontact with the target tissue 110. Lengths from the hinge to thedeployment end of the anchor support 62 within the range of from about0.5 cm to about 1.5 cm are contemplated for the LAA applicationdisclosed herein.

For certain applications, the proximal section 70 is at least about 10%and preferably at least about 20% longer than the distal section 72. Forexample, in one device adapted for the LAA closure application, theproximal section 70 in a six anchor device has a length of about 0.54inches, and the distal section 72 has a length of about 0.40 inches.Each anchor support has an OD of about 0.045 inches. As with previousembodiments, the functional roles and/or the dimensions of the proximaland distal sections can be reversed and remain within the scope of thepresent invention. Optimization of the relative lever arm lengths can bedetermined for each application taking into account a variety ofvariables such as desired device diameter, target lumen or tissueaperture diameter, launch angle and desired pull forces for aiming anddeployment.

The proximal end 71 of the proximal section 70 and distal end 73 ofdistal section 72 are movably secured to the closure catheter 38 in anyof a variety of ways which will be apparent to those of skill in the artin view of the disclosure herein. In the illustrated embodiment, eachanchor support 62 comprises a four segment component which may beconstructed from a single length of tubing by providing an intermediateflex point 74, a proximal flex point 80 and a distal flex point 82.Distal flex point 82 provides a pivotable connection between the anchorsupport 62 and a distal connection segment 84. The distal connectionsegment 84 may be secured to the distal end of actuator 56 by any of avariety of techniques, such as soldering, adhesives, mechanical interfitor others, as will be apparent to those of skill in the art. In theillustrated embodiment, the distal connection segment 84 is secured tothe distal end 66 of the actuator 56 by adhesive bonding.

The proximal flex point 80 in the illustrated embodiment separates theproximal section 70 from a proximal connection segment 86, which isattached to the catheter body 52. In this construction, proximal axialretraction of the actuator 56 with respect to the tubular body 52 willcause the distal connection segment 84 to advance proximally towards theproximal connection segment 86, thereby laterally displacing the flexpoint 74 away from the longitudinal axis of the closure catheter 38. Asa consequence, each of the proximal section 70 and the distal section 72are aimed at an angle which is inclined outwardly from the axis of theclosure catheter 38.

In general, each flex point 80, 82 includes a hinge 81, 83 which may be,as illustrated, a strip of flexible material. The hinges 81 and 83 arepreferably positioned on the inside radius of the flex points 80, 82,respectively, for many construction materials. For certain materials,such as Nitinol or other superelastic alloys, the hinges 81 and 83 canbe positioned at approximately 90° or 180° or other angle around thecircumference of the tubular anchor guide from the inside radius of theflex point.

A tissue anchor 90 is illustrated as positioned within the distalsection 72, for deployment in a generally proximal direction.Alternatively, the anchor 90 can be loaded in the proximal section 70,for distal deployment. A variety of tissue anchors can be readilyadapted for use with the closure catheter 38 of the present invention,as will be appreciated by those of skill in the art in view of thedisclosure herein. In the illustrated embodiment, the tissue anchor 90comprises a tubular structure having a body 92, and one or more barbs94. Tubular body 92 is coaxially movably disposed about an introducer96. Introducer 96 has a proximal section 98, and a sharpened distal tip100 separated by an elongate distal section 102 for slideably receivingthe tissue anchor 90 thereon.

The tissue anchor 90 in the illustrated embodiment comprises a tubularbody 92 having an axial length of about 0.118 inches, an inside diameterof about 0.017 inches and an outside diameter of about 0.023 inches. Twoor more barbs 94 may be provided by laser cutting a pattern in the wallof the tube, and bending each barb 94 such that it is biased radiallyoutwardly as illustrated. The tissue anchor 90 may be made from any of avariety of biocompatible metals such as stainless steel, Nitinol,Elgiloy or others known in the art. Polymeric anchors such as HDPE,nylon, PTFE or others may alternatively be used. For embodiments whichwill rely upon a secondary closure structure such as staples, sutures orclips to retain the LAA or other cavity closed, the anchor may comprisea bioabsorbable or dissolvable material so that it disappears after aperiod of time. An anchor suture 108 is secured to the anchor.

In one embodiment of the invention, the introducer 96 has an axiallength of about 0.250 inches. The proximal section 98 has an outsidediameter of about 0.023 inches and an axial length of about 0.100inches. The distal section 102 has an outside diameter of about 0.016inches and an axial length of about 0.150 inches. The outside diametermismatch between the proximal section 98 and the distal section 102provides a distally facing abutment 104, for supporting the tubular body92 of tissue anchor 90, during the tissue penetration step. A deploymentwire (e.g., a suture) 106 is secured to the proximal end 98 of theintroducer 96. The introducer 96 may be made in any of a variety ofways, such as extrusion or machining from stainless steel tube stock.

Referring to FIGS. 6A-6C, introduction of the tissue anchor 90 intotarget tissue 110 is illustrated following inclination of the anchorsupport 62 with respect to the longitudinal axis of the closure catheter38. Proximal retraction of the deployment wire 106 causes the tissueanchor 90 and introducer 96 assembly to travel axially through thedistal section 72, and into the tissue 110. Continued axial traction onthe deployment wire 106 causes the longitudinal axis of the introducer96 to rotate, such that the introducer 96 becomes coaxially aligned withthe longitudinal axis of the proximal section 70. Continued proximaltraction on the deployment wire 106 retracts the introducer 96 from thetissue anchor 90, leaving the tissue anchor 90 in place within thetissue. The anchor suture 108 remains secured to the tissue anchor 90,as illustrated in FIG. 6C.

In use, the closure catheter 38 is percutaneously introduced into thevascular system and transluminally advanced into the heart and,subsequently, into the left atrial appendage using techniques which areknown in the art. Referring to FIG. 7, the distal end 36 of the closurecatheter 38 is positioned at about the opening of the LAA 16, and theposition may be confirmed using fluoroscopy, echocardiography, or otherimaging. The actuator 56 is thereafter proximally retracted, to inclinethe anchor supports 62 radially outwardly from the longitudinal axis ofthe closure catheter 38, as illustrated in FIG. 8. Preferably, the axiallength of the proximal section 70 of each anchor support 62, incombination with the angular range of motion at the proximal flex point80, permit the flex point 74 to be brought into contact with the tissuesurrounding the opening to the LAA. In general, this is preferablyaccomplished with the distal section 72 inclined at an angle within arange of from about 45° to about 120° with respect to the longitudinalaxis of the closure catheter 38. Actuator 56 may be proximally retracteduntil the supports 62 are fully inclined, or until tactile feedbackreveals that the anchor supports 62 have come into contact with thesurrounding tissue 110.

Following inclination of the anchor supports 62, the deployment wire 106is proximally retracted thereby advancing each of the tissue anchors 90into the surrounding tissue 110 as has been discussed. See FIG. 9. Theanchor supports 62 are thereafter returned to the first, axial position,as illustrated in FIG. 10, for retraction from the left atrialappendage. Proximal retraction on the anchor sutures 108 such as througha tube, loop or aperture will then cause the left atrial appendage wallto collapse as illustrated in FIG. 11. Anchor sutures may thereafter besecured together using any of a variety of conventional means, such asclips, knots, adhesives, or others which will be understood by those ofskill in the art. Alternatively, the LAA may be sutured, pinned, stapledor clipped shut, or retained using any of a variety of biocompatibleadhesives.

In an alternate embodiment, a single suture is secured to a first anchorand slideably connected to the remainder of the anchors such thatproximal retraction of the suture following deployment of the anchorsdraws the tissue closed in a “purse string” fashion. A similar techniqueis illustrated in FIGS. 31A and 31B in U.S. Pat. No. 5,865,791 toWhayne, et al., the disclosure of which is incorporated in its entiretyherein by reference.

The foregoing closure techniques may be accomplished through the closurecatheter, or through the use of a separate catheter. The closurecatheter may thereafter be proximally retracted from the patient, andthe percutaneous and vascular access sites closed in accordance withconventional puncture closure techniques.

The anchor deployment catheter of the present invention may be readilyused to accomplish any of a variety of anastomosis procedures, includingattaching a synthetic vascular graft to an attachment site within avessel, and performing tissue-to-tissue anastomosis of an autologousvein graft such as a graft of the saphenous vein into the coronaryartery. The anastomosis catheter embodiment may also be utilized toprovide intermediate support for a synthetic graft which has alreadybeen positioned at treatment site in a vessel.

Referring to FIG. 12, there is illustrated a schematic side elevationalcross-section of a vessel 122 having a defect 124 such as an aneurysm. Agraft 120 is illustrated spanning the defect 124, and overlapping atleast a portion of healthy vessel wall both proximally and distally ofthe aneurysm 124.

An anastomosis catheter 126 is illustrated in position within a proximalend of the graft 120. The anastomosis catheter 126 is provided with aplurality of anchor supports 62 near a distal end 36 thereof. Eachanchor support comprises a proximal section 70, a distal section 72 anda hinge point 74.

Referring to FIG. 13, the graft 120 and vessel 122 have been penetratedby the sharpened tip 100 of an introducer 96, which has been deployed asdiscussed previously herein. The introducer 96 carries an anchor 92thereon. In the illustrated embodiment, proximal traction on adeployment wire which has previously been discussed causes theintroducer 96 to introduce the anchor 92 into the treatment site.Continued traction on the deployment wire retracts the introducer 96into the proximal section 70 of the anchor support 62, leaving theanchor 92 in position.

As illustrated in FIG. 14, the anchor 92 is provided with one or moredistal barbs 94 for resisting proximal motion of the anchor 92, and oneor more proximal barbs 95 for resisting distal migration of the anchor92. In this manner, the anchor 92 will remain in position to secure thegraft 120 to the vessel 122.

The anastomosis catheter 126 can be adapted for use in a variety ofgraft implantation and attachment methods. For example, a tubular graftwhich has been attached such as by the use of self expandable or balloonexpandable stents at the proximal and distal ends of the graft mayrequire intermediate support to maintain patency of the central lumen inbetween the axial ends. Intermediate support may be accomplished byeither positioning additional stents within the tubular graft, or byusing the anastomosis catheter 126 to anchor the graft to the nativevessel wall. Two or more anchors may be provided in each anchor support.In this manner, the anastomosis catheter 126 may positioned at a firstposition where a first plurality of anchors are deployed through a graftinto the native vessel, and then repositioned to a second position wherea second plurality of anchors may be deployed to retain or secure thegraft. Additional anchor supports and/or anchors may be provided on theanastomosis catheter 126, depending upon the number of anchors desirablypositioned along the axial length of a graft.

Alternatively, the anastomosis catheter 126 may be utilized to implant atubular graft. In this embodiment, the tubular graft is coaxiallydisposed about the exterior of the anastomosis catheter 126. Thecatheter is positioned at a treatment site, and the anchor supports areinclined to the axial orientation thereby positioning the vascular graftagainst the vessel wall. Anchors are deployed as has been discussed. Theanchors may be secured to the graft directly such as through the use ofa tether or other attachment structure, or may be independent from thegraft but secured thereto in situ by the proximal and distal barbs orother structural arrangement which will become apparent to those ofskill in the art in view of the disclosure herein. Thus, althoughreferred to generally herein as an anastomosis catheter 126, thisembodiment of the invention may also be considered a transluminal graftimplantation catheter or graft attachment catheter as will be apparentto those of skill in the art.

Referring to FIGS. 15A-15G, there are illustrated a variety of tissueanchors which may be used in the tissue closure or attachment device ofthe present invention. Each of FIGS. 15A and 15B disclose an anchorhaving a body 92, a distal tip 101, and one or more barbs 94 to resistproximal movement of the anchor. An aperture 107 is provided to receivethe anchor suture. The embodiments of FIGS. 15A and 15B can be readilymanufactured such as by stamping or cutting out of flat sheet stock.

The anchor illustrated in FIG. 15C comprises a wire having a body 92 anda distal tip 101. The wire preferably comprises a super-elastic alloysuch as Nitinol or other nickel titanium-based alloy. The anchor iscarried within a tubular introducer, in a straight orientation, forintroduction into the tissue where the anchor is to reside. As the body92 is advanced distally from the carrier tube, the anchor resumes itslooped distal end configuration within the tissue, to resist proximalretraction on the wire body 92.

FIG. 15D illustrates a tubular anchor, which may be manufactured from asection of hypotube, or in the form of a flat sheet which is thereafterrolled about a mandrel and soldered or otherwise secured. The anchorcomprises a distal tip 101, one or more barbs 94, and an aperture 107for securing the anchor suture. The anchor of FIG. 15D may be carried byand deployed from the interior of a tubular anchor support as has beendiscussed. Alternatively, the anchor of FIG. 15D can be coaxiallypositioned over a central tubular or solid anchor support wire.

FIG. 15E illustrates an anchor which may be formed either by cuttingfrom tube stock or by cutting a flat sheet such as illustrated in FIG.15F which is thereafter rolled about an axis and soldered or otherwisesecured into a tubular body. In this embodiment, three distal tips 101in the flat sheet stock may be formed into a single distal tip 101 inthe finished anchor as illustrated in FIG. 15E. One or more barbs 94 maybe formed by slotting the sheet in a U or V-shaped configuration asillustrated. The anchor in FIG. 15E is additionally provided with one ormore barbs 95 which resist distal migration of the anchor. This may bedesirable where the anchor is implanted across a thin membrane such asattachment of a synthetic graft, or in other applications such astissue-to-tissue anastomosis where distal as well as proximal migrationis desirably minimized.

Referring to FIGS. 16 through 18, there is disclosed an alternateanastomosis anchor 90 in accordance with the present invention. Anchor90 comprises a proximal end 130, a distal end 132 and a central lumen134 extending therebetween. Central lumen 134 allows the anchor 90 to bepositioned on an introducer 96 as is illustrated in FIG. 17, and hasbeen previously discussed.

The anchor 90 is provided with at a least first proximal projection 136and a second proximal projection 138. First and second proximalprojections 136 and 138 are designed to enlarge radially outwardly inresponse to axial shortening of the anchor 90. Thus, in an axiallyelongated configuration such as that illustrated in FIG. 17, the firstand second proximal projections 136 and 138 extend generally in parallelwith the longitudinal axis of the anchor 90. A distally facing tissuecontact surface 144 is forced to incline radially outwardly in responseto axial shortening of the anchor 90, as will be apparent to those ofskill in the art in view of the illustration in FIG. 16. Althoughillustrated with two proximal projections positioned at approximately180° apart from each other, three or four or more proximal projectionsmay be provided, preferably evenly distributed about the circumferenceof the anchor 90.

At least a first distal projection 140, and preferably a second distalprojection 142 are provided on the tubular body 92 spaced distally apartfrom the proximal projections. First and second distal projections 140and 142 similarly expand or enlarge radially outwardly in response toaxial compression or other shortening of the anchor 90. Axial separationbetween the first proximal projection 136 and first distal projection140 allows the anchor 90 to secure a graft 126 or other structure to theinterior wall of the vessel 120 or other tissue plane as illustrated inFIG. 18, by sandwiching the wall of the graft 126 and vessel wall 120between distally facing tissue contact surface 144 and proximally facingtissue contact surface 146. The anchor 90 can be deployed from theintroducer 96, utilizing any of the deployment catheters disclosedelsewhere herein.

The radial enlargement of the proximal and distal projections isaccomplished by axially shortening the anchor 90 along its longitudinalaxis. This may be accomplished by axially compressing a compressionactuated embodiment, by releasing a restraint on a biased embodiment, orby activating a memory metal embodiment such as by exposing it to acurrent or temperature change.

In a compression actuated embodiment, proximal movement of proximal end130 is inhibited by seating the proximal end 130 against a stop surfacesuch as on the proximal section 98 of an introducer 96, as illustratedin FIG. 17. The distal end 132 is thereafter advanced proximally, suchas by proximal traction on a proximal force transmitter 148 which may bea suture 150. Suture 150 may extend in a loop through a plurality ofapertures 152, extending through the proximal and distal projections.Alternatively, the suture 150 may extend alongside the anchor 90 orthrough central lumen 134 depending upon the tolerance between thecentral lumen 134 and the introducer 96. Alternative proximal forcetransmitter structures such as pull wires and moveable cores may also beutilized, as will be apparent to those of skill in the art.

The anchor 90 may be manufactured in a variety of ways, such as bycutting or etching from a metal or polymeric tube. Preferably, theanchor 90 is laser cut from a Nitinol or steel tube having an outsidediameter within the range of from about 0.014″ to about 0.038″ and anaxial length within the range of from about 0.050″ to about 0.250. Theaxial length of each of the distally facing tissue contact surface 144and proximally facing tissue contact 146 is within the range of fromabout 0.010″ to about 0.060″. The wall thickness of the tube is withinthe range of from about 0.002″ to about 0.012″. Full axial compressionof most metal tube embodiments will bend the metal beyond its elasticlimit at each apex on the various projections, such that the suture 150may be removed from the anchor 190 following deployment and the anchorwill remain in its deployed (axially compressed) configuration asillustrated in FIG. 18.

In a biased embodiment, the anchor may be formed from a memory metalsuch as a NiTi alloy in the form illustrated in FIG. 18. The anchor isreduced to its introduction crossing profile by axial elongation andretained in that form by axial traction or by capture within a removabletubular sleeve. Once deployed from the tubular catheter body or otherrestraining structure, or upon removal of the axial traction, the anchorassumes the deployed configuration illustrated in FIG. 20.

Although the present invention has been described in terms of certainpreferred embodiments, other embodiments will become apparent to thoseof skill in the art in view of the disclosure herein. Accordingly, thescope of the invention is not intended to be limited by the specificdisclosed embodiments, but, rather, by the attached claims.

What is claimed is:
 1. An anchor for securing a graft to a vessel wall,comprising: a body, having a proximal end, a distal end, and alongitudinal axis; at least one proximal arm on the body for resistingdistal movement of the anchor through tissue; and at least one distalarm on the body for resisting proximal movement of the anchor throughtissue; wherein the proximal and distal arms are moveable between afirst position in which the cross section of the anchor is minimized anda second position in which the arms are deployed.
 2. An anchor as inclaim 1, wherein the arms are biased in the direction of the secondposition.
 3. An anchor as in claim 1, wherein the arms are moveable intothe second position in response to axial shortening of the anchor.
 4. Ananchor as in claim 1, wherein the arms and body are integrally formedfrom a tube.
 5. An anchor as in claim 1, comprising from two proximalarms to about six proximal arms.
 6. An anchor as in claim 1, comprisingfrom two distal arms to about six distal arms.
 7. An anchor as in claim1, comprising a nickel titanium alloy.
 8. An anchor as in claim 1,wherein the at least one proximal arm and the at least one distal armare integral with the body.